The image forming apparatus (MFP: Multi-Functional Peripheral) forms a visible image corresponding to an image data and outputs the visible image onto a recording medium as an output image.
In the related art, when the power source of the MFP is ON, when the power source returns from a sleep mode, or the like, the MFP executes a warm-up operation in which a fixing device is heated to a predetermined fixing temperature before starting an image forming operation. The fixing temperature at this time is a temperature that can reliably fix a color image.
However, the temperature at which a monochrome image can be fixed is lower than the temperature at which a color image can be fixed. For that reason, when a customer tries to form the monochrome image, unnecessary standby time is imposed on the customer.